Chelating agents are sometimes used in order to reduce the metallic taste and astringency of oral care compositions containing a metal ion source. Tetrasodium pyrophosphate (TSPP) and tetrapotassium pyrophosphate (TKPP) are two commonly used chelating agents.
However, it has been observed that such dentifrice compositions containing efficacious amounts of TSPP and TKPP as chelating agents exhibit phase separation when the dentifrice base includes certain commonly used thickening gum systems.
A need therefore exists for metal ion-containing dentifrice compositions which have reduced metallic taste and astringency, and which have improved resistance to phase separation.